>> reporter: diane, an official tells abc news tonight,s the fbi discovered hundreds, if not thousands, of e-mails between david petraeus and paula broadwell on her computer, an affair that petraeus is claiming did not begin until he left the army. a friend close to petraeus says the general was "shocked and surprised" to learn broadwell had been sending anonymous threatening e-mails to jill kelley, the petraeus family friend who was so alarmed by the e-mails, she called the fbi. those friends also tell us the general's wife, holly petraeus, is furious with her husband. you see her here at his confirmation hearings back in august of 2011, broadwell sitting just a few seats away. petraeus insists they weren't having an affair then, which leads us to the first big question -- when did the affair begin? petraeus' friends claim it started around november 2011, two months after he took over the cia, an important point, since he could be tried under military law for adultery. >> it didn't begin when he was in the army. >> reporter: but many who know the general suspect it began months earlie